Their shows possession (their car), there points to a place or says that something exists (there it is; there is a problem), and they're is simply the short form of they are (they're late). The quickest test: if you can replace the word with "they are," use they're; if it answers the question "whose?", use their; if neither fits, the answer is there.
These three words are homophones: they sound identical but mean completely different things. That is the only reason they get muddled — and it is why a spellchecker will not rescue you, because all three are correctly spelled words. Only a reading eye catches the wrong one.
Their is the possessive form of they. It shows that something belongs to a group or, increasingly, to a single person. It sits right beside my, your, our and its, and it almost always comes before a noun: their house, their decision, their mistake.
Do not confuse it with theirs, which is a possessive pronoun that stands alone with no noun after it: The blue car is theirs. Both show ownership, but their needs a noun and theirs does not.
There does two jobs. First, it points to a place — it is the opposite of here, and it literally contains the word here: Put it over there. We drove there last summer. Second, it introduces the idea that something exists, usually in the phrases there is, there are, there was and there seems to be: There is a message for you. There are three reasons.
The contraction there's means "there is" or "there has" — never "belonging to them": There's a spider in the bath. There's been a mistake.
You will also meet there in fixed expressions like there you go, there, there (said to comfort someone) and been there, done that. These all trace back to the idea of place or existence, so the spelling stays there.
They're is a contraction of they are, and nothing else. The apostrophe stands in for the missing letter "a" in are. Before you write they're, expand it in your head: if "they are" makes sense in the sentence, you are right; if it sounds wrong, you need their or there instead.
Almost every mistake with these words is a slip of the fingers, not a misunderstanding. Here are the classic errors and their fixes:
The first line is the sentence that trips everyone up, because it uses all three in a row. Read it out slowly — "they are over there with the friends that belong to them" — and each choice becomes obvious.
There's means "there is" or "there has." Theirs is a thing belonging to them. Note that theirs never takes an apostrophe, even though it shows possession — just like ours, yours and hers: That table is theirs, but there's a chair missing.
You will sometimes be told that their can only be plural, so "Someone left their bag" must be wrong. That is a myth. Singular their — used for one person of unknown or unspecified gender — has appeared in English for more than 600 years, in Chaucer, Shakespeare and Jane Austen, and it is now accepted by Merriam-Webster and by both the AP and Chicago style guides. Everybody grabbed their coat is perfectly correct.
In careful writing, match there is/are to the noun that follows: There are three options, not There is three options. In everyday speech people constantly say there's before plurals ("there's loads of people"), which is fine when talking — but tighten it in formal writing.
Because their is so common, some people stretch it into theirself or theirselves. Standard English uses themselves (and, for a single person, themself is now accepted too): They fixed it themselves, never theirselves.
No. Some editors discourage it because it can be wordy — There are many people who disagree trims neatly to Many people disagree — but that is a style tip, not a grammar rule. There is and there are are correct, and often the most natural way to say that something exists.
Look inside each word:
None at all. This is one corner of English where American and British usage agree completely — same spellings, same meanings, same rules, and the same tendency to mix them up. There is no British "theyre" or American "thier"; the errors and the fixes are identical on both sides of the Atlantic. Both varieties now accept singular their, and both slip into there's before plurals in casual speech.
Test each word. If you can replace it with "they are," use they're. If it shows ownership and answers the question "whose?", use their. If it points to a place or says something exists (there is, there are), use there. Only they're takes an apostrophe, because it hides the missing "a" in "are."
It is their house. "Their" shows who owns the house — it belongs to them, exactly like my house or our house. "There house" is always wrong. Quick check: swap in another possessive such as "our." Since "our house" works, the possessive their is the correct choice here.
Look inside each word. There contains here, and both point to a place. Their contains heir, and an heir owns things, so their means ownership. They're has an apostrophe standing in for the missing "a" in "they are" — so expand it to "they are" to check that it fits.
Yes. Singular "their" refers to one person of unknown or unspecified gender: "Someone forgot their coat." This usage is centuries old — Chaucer, Shakespeare and Austen all used it — and Merriam-Webster, AP and Chicago style now accept it. Despite the persistent old myth, it is not a grammatical error.
"There's" is a contraction of "there is" or "there has": "There's a message for you." "Theirs" is a possessive pronoun meaning the thing belonging to them: "The blue car is theirs." Note that theirs never takes an apostrophe, even though it shows possession — like ours, yours and hers.
